Telephone-exchange system.



C. W. KECKLER.

TELEPHONE EXCHANGE SYSTEM.

APPLICATION HLED APR. 24. 1911. 1,257,363. Patented Feb. 26,1918.

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TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED APR.24. 1911.

Patented Feb. 26, 1918.

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UNITED STATES PATENT OFFICE;

CHARLES W. KECKLER, OF NEWARK, NEW JERSEY, ASSIGNOR .TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Feb. 26, 1918.

Application filed. April 24, 1917. Serial No. 164,173.

To all whom 2'25 may concern:

Be it kIlOwn that I, CHARLES W. KEGKLER, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems, and more particularly to such systems of the common battery type, its object being to provide an improved sig naling means for systems of this character.

In accordance with a feature of this invention, a link circuit in which there is a signaling device and a supervisory relay is provided with a two-step relay, which cooperates, when energized, with a supervisory relay to cause the intermittent operation of the signaling device to furnish a characteristic Signal.

This invention is shown in the accomnanving drawings, wherein,

Figure 1 shows two ordinary telephone line circuits and a link circuit containing one embodiment of this invention, in which an answering supervisory signaling device is intermittently operated to furnish a signal; '1-

Fig. 2 shows a link circuit containing another embodiment of this invention, in which a calling supervisory signaling device is intermittently operated to furnish a recall signal from the connected calling line;

Fig. 3 shows a link circuit containing another embodiment of this invention, in which an answering supervisory signaling device is intermittently operated to furnish a recall signal from a connected line, and in which the connection and disconnection of the operators telephone set with the calling line is automatically effected; and

Fig. 4. shows a link circuit in which there is a signaling device intermittently operated at one rate to furnish a ringing signal, and at another rate to furnish a recall signal from a connected calling line, and another signaling device operated continuously to furnish a disconnect signal from either the connected calling or called line.

It is believed that this invention will be fully understood from a description of the operation of the system shown in the drawings, and it will be so described.

Figure 1.

Subscriber A, in initiating a call, signals the central oflice in the usual manner, whereupon the operator responds by inserting answering plug 5 of cord circuit G into line jack 6. Relay 7 is thereupon partially energized and cutoff relay 8 operated over a circuit from battery through the right-hand winding of relay 7 sleeve contacts of the answering plug 5 and line jack 6 and the winding of cutofi relay 8 to ground. When the circuit is established through the righthand winding of relay 7, this relay is only energized sufficiently, to attract its lefthand armature, but when both of its wind ings are included in circuit, the relay is then energized sufiiciently to attract all of its armatures. When the answering plug of the cord circuit is inserted into the line jack, answering supervisory relay 9 also operates. The operator may now actuate listening key 10 to connect the operators telephone set with the cord circuit. Upon being advised that the line desired is that of subscriber B, the operator restores the listening key to normal position and inserts calling plug into line ack 16, whereupon the called subscriber is signaled in the usual manner. a

At the conclusion of the conversation, subscriber A restores the receiver to the switchhook, causing supervisory relay 9 to release. The left-hand winding of relay 7 is there upon included in a circuit from battery through lefthand alternate contact of relay 7, left-hand winding thereof,.contact 11 of listening key 10, normal contact of relay 7, and normal contact of relay 9 to ground. Relay 7 is thereupon fully energized, attracts all of its armatures, and establishes a locking circuit for itself from battery through the left-hand alternate contact and left-hand winding thereof, contact 11 of listening key 10, and middle alternate contact of relay 7 to ground. Answering super-' visory lamp 12, upon the release of answering supervisory relay 9, is continuously lighted to furnish a disconnect signal.

If, before the plugs are withdrawn from the jacks, subscriber A initiates another call by removing the receiver from the switch hook, supervisory relay 9 is actuated, there by causing the intermittent operation of answering supervisory lamp 12, over a circuit from battery through the left-hand alternate contact of relay 7, lamp 12, alternate contact of relay 9, right-hand alternate con tact of relay 7 and interrupter 13 to ground. The intermittent operation of lamp 12 furnishes arecall signal to the operator. The operator may now, in response to the recall signal, actuate the listening key to connect the telephone set to the cord circuit. The operation of the listening key opens a circuit through the left-hand winding of relay 7, whereupon it releases its right-hand and middle armatures.

Figure 2.

If in answering a call from subscriber A, the operator employs the cord circuit of Fig. 2, the insertion of answering plug 5 into the line jack 6 causes the partial energization of two-step relay 17 and the operation of answering supervisory relay 9. Two-step relay 17 attracts its upper armature only. The operator may actuate listening key 10 to connect the operators telephone set to the cord circuit. Upon being advised that the line desired is that of subscriber B, the operator inserts the calling plug 15 into the line jack 16 thereof, causing the operation of calling sleeve relay 2 1 and cutofi relay 18. The operation of relay 24 causes calling supervisory lamp 19 to be lighted. Subscriber B may be signaled in any desired manner, and in responding, causes the opera tion of supervisory relay 25, thereby eli'acing supervisory lamp 19.

Upon finishing the conversation, the subscribers restore the receivers to the switch hooks, thereby causing the release of supervisory relays 9 and 25. The release of relay 25 causes calling supervisory lamp 19 to be lighted to furnish a disconnect signal, and the release of relay 9 causes answering supervisory lamp 26 to be lighted to furnish a disconnect signal. The release of relay 9 also completes a circuit for the lower winding of two-step relay 17 from battery through contact 11 of listening key 10, lower winding of relay 17, normal contact thereof, normal cont-act of relay 9 and upper alternate contact of relay 17 to ground. Relay 17 is thereupon fully energized and attracts all. of its armatures, establishing a locking circuit for itself through its middle alternate contact to ground.

Should subscriber A .desire to initiate another call before the plugs are withdrawn from the jacks, the removal of the receiver from the switchhook causes the operation of supervisory relay 9, whereupon answering supervisory lamp 26 is efi'aced, and relay 27 is operated over a circuit from battery through the winding of relay 27 lower alternate contact of relay 17, alternate contact of relay 9, and upper alternate contact of relay 17 to ground. The operation of relay 27 stops the continuous operation of calling supervisory lamp 19 and causes the intermittent operation thereof over a circuit from battery through lamp 19, alternate contact of relay 27 and interrupter 13 to ground. This intermittent operation of the calling supervisory lanip 19 serves as a recall signal to the operator. The operator, in re sponding to this recall signal, actuates the listening key 10 which connects the telephone set to the cord circuit and opens the lower winding of relay 17, which thereupon releases its lower and middle armatures. Relay 27 is thereby released and stops the intermittent operation of calling supervisory lamp 19.

Figure 5.

Assuming that the operator, in answering a call from subscriber A, employs the cord circuit of Fig. 3, the insertion of the answering plug 5 thereof into line jack 6 causes the operation of relay 30 and cutoff relay 8. Upon the operation of relay 30, the super visory relay 9 is connected to the answering end of the cord circuit and is operated over the connected calling line. Answering supervisory relay 9, in operating, causes the partial energization of relay 37 over a circuit from battery through answering supervisory lamp 12, alternate contact of relay 9, contact 38 of relay 37, left-hand winding thereof and lower alternate contact of relay 30 to ground. This partial energization of relay 37 is sufficient to attract its two lefthand armatures, whereupon a locking circuit for the left-hand winding of relay 37 is established through contact 39 thereof. The operators telephone set is normally connected to the cord circuit through normally closed contacts of relay 40. The onerator being advised that connection is desired with line B, inserts calling plug 15 into line jack 16, whereupon relay 10 and cutofl' relay 18 operate. Relay 40, in operating, disconnects the operators telephone set from the cord circuit and connects thereto calling supervisory relay 4C1. Relay 4:0, in operating, also causes calling supervisory lamp 42 to be lighted. Subscriber B may now be signaled in any desired manner, and in responding, causes the operation of supervisory relay 41, which efi'aces supervisory lamp 42.

Upon finishing the conversation, the subscribers restore the receivers to the switch hooks, whereupon supervisory relays 9 and ell release, respectively causing answering and calling supervisory lamps 12 and 42 to be lighted to furnish disconnect signals. Re-

lay 9, in releasing, also completes a circuit for the right-hand winding of relay 37, which may be traced from battery through the right-hand winding of relay 37, contacts 43 and 44 thereof, normal contact of relay 9 and lower alternate contact of relay 30 to ground. Relay 37 is thereby completely energized and attracts all of its armatures, and, in so doing, completes a locking circuit for its right-hand winding through contact 45 of relay 37, contact 46 of an emergency key and the lower alternate contact of relay 30 to ground.

If, before the plugs are removed from the line jacks, subscriber A initiates another call by removing the receiver from the switchhook, supervisory relay 9 is operated, causing the intermittent operation of answering supervisory lamp 12 over a circuit from battery through lamp 12, alternate contact of relay 9, contact 47 of relay 37 and interrupter 13 to ground. The intermittent operation of this lamp serves as a recall signal to the operator. In responding to this signal, the operator removes the calling plug from the jack of the line, thereby releasing relay 40 which connects the telephone set to the cord circuit. The intermittent operation of lamp 12 may be stopped by opening contact 46 of the emergency key, which opens up the locking circuit through the right-hand winding of relay 37, whereupon this relay releases its two right-hand armatures.

Should the operator, in answering a call from subscriber A, employ the cord circuit of Fig. 4, the insertion of the answering plug 5 thereof into the line jack 6 causes the partial energization of two-step relay 57 and the operation of supervisory relay 9. The partial energization of relay 57 attracts the right-hand armature thereof. The operator may now actuate the listening key 10 to connect the telephone set to the cord circuit. Upon being advised that connection is desired with the line of subscriber B, the listening key is restored to normal position and the calling plug 15 inserted into the line jack 16, whereupon two-step relay 58 is partially energized to attract its right-hand armature. The attraction of the right-hand armature of relay 58 causes the intermittent operation of lamp 59 over a circuit from battery through interrupter 60, contacts 61 and 62 of two-step relay 58, contact 63 of two-step relay 57 lamp 59, alternate contact of supervisory relay 9 and contact 64 of two-step relay 57 to ground. The intermittent operation of lamp 59 serves as a ringing signal to the operator, and continues until supervisory relay 65 is actuated. Upon the actuation of relay 65, when the called subscriber responds, circuit is completed through the left-hand winding of relay 58, whereupon this relay is fully energized, attracting all of its armatures. In being fully energized, a locking circuit for the left-hand winding of relay 58 is established through contact 66 thereof. The open-, ing of contact 62 stops the intermittent operation of the lamp 59.

Upon finishing the conversation, the subscribers restore the receivers to the switchhooks, causing the release of supervisory relays 9 and 65, whereupon lamp 67 is lighted over a path from battery through lamp 67 contact 68 of relay 58 and normal contact of relay 65 to ground. There is another circuit for this lamp 67, which may be traced from battery through the lamp, normal contact of relay 9 and contact 64 of relay 57 to ground. It will be noted, therefore, that this lamp 67 may be lighted tofurnish a disconnect signal from either the calling or the called line. Upon the release .of relay 9, a circuit is established for the left-hand winding of relay 57, which may be traced from battery through the left-hand winding of the relay, contact 11 of listening key 10, contact 69 of relay 57, normal contact of relay 9 and contact 64 of relay 57 to ground. Relay 57 is thereby completely energized and attracts all of its armatures, and in so doing, establishes a locking circuit for the left-hand winding thereof through contact 70.

' If, before the plugs are withdrawn from the jacks, subscriber A initiates another call, the removal of the receiver from the switchhook causes the operation of the su-' pervisory relay 9, whereupon the lamp 59 will be intermittently operated over a circuit from battery through interrupter 71, contact 72 of relay 57 lamp 59, alternate contact of relay 9 and alternate contact 64 of relay 57 to ground. The number of interruptions per unit length of time by interrupter 71 is difierent from that produced by interrupter 60, so that the intermittent operation of lamp 59 when interrupter 71 is in circuit furnishes a recall signal which differs from that known as the ringin signal i'nrnished by the lamp 59 when interrupter 60 is in circuit. The operator, in responding to this recall signal, actuates the listening key 10, whereupon the locking circuit for the left-hand winding of relay 57 is opened and the relay releases its left-hand armatures, thereby stopping the intermittent operation of lamp 59. Upon receiving the proper in: structions, the operator may restore the listening key to normal position and withdraw the plug 15 from the jack, and establish any other connection desired. The removal of this calling plug from the line jack restores relay 58 to normal.

The two-step relays 7, 17 ,37 and 57 are of the same general construction, and function in identically the same manner in all of the circuits, the only difference being in the number of contacts controlled by the different relays.

What is claimed is:

1. A telephone exchange system comprising telephone lines terminating in a central ofiice, a link circuit thereat, a relay for the link circuit partially energized upon a connection of the link circuit with one of the lines, a supervisory relay for the link circuit, a signaling device therefor, and interrupter mechanism brought into circuit with the signaling device upon the complete energization of the first mentioned relay and upon the energization of the Supervisory relay.

2. A telephone exchange system comprising telephone lines, a link circuit, a supervisory relay for the link circuit, a relay for the link circuit partially energized upon connection of the link circuit with one of the lines and completely energized when the supervisory relay is ,deenergized, a signaling device, and interrupter mechanism brought into circuit with the signaling device upon the energization of the supervisory relay while the other relay is completely energized.

3. A telephone exchange system comprising telephone lines, a link circuit, a supervisory relay for the lmk circuit, an operators telephone set, a switching device controlling the connection of the operators telephone set with the link circuit, a local circuit relay partially energized upon connection of the link circuit with one of the lines and completely energized when the supervisory relay is deenergized, a locking circuit for the local circuit relay including a contact of the switching device completed upon the complete energization thereof, a signaling device, and interrupter mechanism brought into circuit with the signaling device upon the subsequent energization of the supervisory relay while the local circuit relay is completely energized.

4;. A telephone exchange system comprising telephone lines, a link circuit, a supervisory relay for the link circuit, an operators telephone set, a listening key controlling the connection of the operators telephone set with the link circuit, a local circuit relay partially energized upon connection of thelink circuit with one'of the lines and completely energized when the supervisory relay is denergized, a locking circuit for the local circuit relay including a contact of the listening key completed upon the complete energization thereof, a signaling device, and interrupter mechanism brought into circuit with the signaling device upon the subsequent energization' of the supervisory relay while the local circuit relay is completely energized. V

5. A telephone exchange system comprising telephone lines, a link circuit, a superyisory relay for the link circuit, a relay par tially energized upon connection of the link circuit with one of the lines and completely ene gized en he superv s y r lay is deenergized, a signaling device, interrupter mechanism, and a circuit for the signaling device and the interrupter mechanism including contacts of the supervisory relay and the second mentioned relay.

6. A telephone exchange system comprising telephone lines, a link circuit, a supervisory relay for the link circuit, a relay partially energized upon connection of the link circuit with one of the telephone lines, a signaling device, interrupter mechanism, and a circuit for the signaling device and'the interrupter mechanism open at two points, one being closed upon the complete energizetion of the second mentioned relay when the supervisory relay is deenergized and the other being closed by the subsequent energization of the supervisory relay.

7. A telephone exchange system comprising telephone lines, a'link circuit, a supervisory relay for the link vcircuit, a relay partially energized upon connection of the link circuit with one of the lines, a signaling device, interrupter 'mechanism, and a circuit for the signaling device and the interrupter mechanism established upon the complete energization vof the second mentioned relay followed by the energization of the supervisory relay.

In witness whereof, I hereunto subscribe my name this 20th day of April, A. 1)., 1917.

CHARLES w. KECKLER.

genie; cf this patent may be obtained for five cents each, by addressing the ,Oommissioner e! Patents,

Washington, D. (3. 

